java问题01-swing问题（监听器、面板与按钮）

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.event.*;

import java.util.Random;

import javax.swing.*;

public class JFrameTest extends JFrame implements ActionListener {

static int i = 0;

Random r = new Random();

JButton[] jb = new JButton[5];

public static void main(String[] args) {

new JFrameTest();

}

public JFrameTest() {

for (int i = 0; i < jb.length; i++) {

jb[i] = new JButton("颜色" + i + "号");

}

this.add(jb[0], BorderLayout.EAST);

this.add(jb[1], BorderLayout.SOUTH);

this.add(jb[2], BorderLayout.WEST);

this.add(jb[3], BorderLayout.NORTH);

this.add(jb[4], BorderLayout.CENTER);

// 注册监听

jb[0].addActionListener(this);

jb[0].setActionCommand("jb[0]");

jb[1].addActionListener(this);

jb[1].setActionCommand("jb[1]");

jb[2].addActionListener(this);

jb[2].setActionCommand("jb[2]");

jb[3].addActionListener(this);

jb[3].setActionCommand("jb[3]");

this.setTitle("颜色案例");

this.setSize(600, 500);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.setResizable(true);

this.setVisible(true);

}

public void paint(Graphics g) {

super.paint(g);

System.out.println("********" + (i++));

}

public void actionPerformed(ActionEvent e) {

if (e.getActionCommand().equals("jb[0]")) {

jb[4].setBackground(new Color(r.nextInt(256), r.nextInt(256), r

.nextInt(256), r.nextInt(256)));

} else if (e.getActionCommand().equals("jb[1]")) {

jb[4].setBackground(new Color(r.nextInt(256), r.nextInt(256), r

.nextInt(256), r.nextInt(256)));

} else if (e.getActionCommand().equals("jb[2]")) {

jb[4].setBackground(new Color(r.nextInt(256), r.nextInt(256), r

.nextInt(256), r.nextInt(256)));

} else if (e.getActionCommand().equals("jb[3]")) {

jb[4].setBackground(new Color(r.nextInt(256), r.nextInt(256), r

.nextInt(256), r.nextInt(256)));

} else {

System.out.println("啥都不做");

}

this.repaint();

}

}